WASMテキストモードのプリプロセスをJSでできるようにしてみた。

test.mwat

;; block
{@
$.X = 0x1;
$.Y = 2;
$.Z = 0x3;
}

;; code
(module
  (export "test" (func $test))
  (memory $memory 1)
  (export "memory" (memory $memory))
  
  (func $test (result i32)
    i32.const @X;; comment
    i32.const {$ $.X + $.Y }
    i32.add
    i32.const {
      ++$.X; return $.X + $.Y;
    }
    i32.mul
  )
)

プリプロセス後.wat

;; block

 ;; code
 ( module
 ( export "test" ( func $test ) )
 ( memory $memory 1 )
 ( export "memory" ( memory $memory ) )
 ( func $test ( result i32 )
 i32.const 1 ;; comment
 i32.const 3
 i32.add
 i32.const 4
 i32.mul
 )
 )